I have mordanted my bleached 10/2 cotton skeins a second time with aluminum acetate, which involved heating at 100 for an hour (it actually got up to 150 at one point, oops), cooling overnight in the mordant bath, and hanging outside to dry this morning. This afternoon they are not yet dry, but they do have a strong vinegar-like smell which I think must be the acetic acid Liles mentioned. So I gather I ought to wait until that smell dissipates, which could be several days, before I dye the yarn. Meanwhile, my madder bath is starting to get moldy. I have a pretty high tolerance for decomposition and stinky things, but in a few more days it will be yucky. What to do?